Method and device in a camera network system

Abstract

There is provided a method performed by a device in a network camera system. First and second encoded image data representing the same scene are received (S02, SO4) over a network. The first and the second encoded image data are collected under the same light condition, albeit using different camera parameters. In particular, the second encoded image data is collected using camera parameters which simulate that the second encoded image data is collected under a darker light condition. A ratio of received data amount per time unit of the first encoded image data to received data amount per time unit of the second encoded image data is determined (S06) and the ratio is then used (S08) as an indication of a level of noise in the first encoded image data.

The invention claimed is: 
     
       1. A method performed by a device in a network camera system, comprising:
 receiving, over a network, first encoded image data representing a scene, the first encoded image data being collected by a camera under a first light condition using first camera parameters, 
 receiving, over the network, second encoded image data representing the same scene, the second encoded image data being collected by the camera under the first light condition using second camera parameters which are different from the first camera parameters in that they are modified to increase a level of noise in image data collected by the camera, thereby simulating that the second encoded image data is collected under a second, darker, light condition, 
 determining a ratio of received data amount per time unit of the first encoded image data to received data amount per time unit of the second encoded image data, and 
 using the ratio as an indication of a level of noise in the first encoded image data. 
 
     
     
       2. The method of  claim 1 , wherein the ratio is determined by comparing a bandwidth needed for transmitting the first encoded image data and the second encoded image data, respectively, over the network. 
     
     
       3. The method of  claim 1 , wherein the ratio is determined by comparing rates at which the first encoded image data and the second encoded image data, respectively, are written to a storage space. 
     
     
       4. The method of  claim 1 , wherein the step of using the ratio as an indication of a level of noise in the first encoded image data comprises:
 checking if the ratio is larger than a predefined threshold, and if so 
 determining that an action needs to be taken in order to reduce the level of noise in future image data representing the scene collected by the camera under the first light condition using the first camera parameters. 
 
     
     
       5. The method of  claim 4 , wherein the step of determining that an action needs to be taken comprises:
 determining that additional lighting is needed in the scene when the camera uses the first camera parameters to collect image data of the scene under the first light condition. 
 
     
     
       6. The method of  claim 4  wherein the step of determining that an action needs to be taken comprises determining that the camera needs maintenance. 
     
     
       7. The method of  claim 6 , wherein the maintenance comprises maintenance of a cooling system of the camera, replacement of a lamp in the camera, or cleaning or replacing a housing or a lens of the camera. 
     
     
       8. The method of  claim 4 , further comprising selecting the predefined threshold depending on the scene. 
     
     
       9. The method of  claim 1 , wherein the first and the second camera parameters comprise at least one of gain, aperture, and exposure time. 
     
     
       10. The method of  claim 9 , wherein the second camera parameters are different from the first camera parameters in that they are modified to increase at least one of gain, aperture, and exposure time. 
     
     
       11. A non-transitory computer-readable medium with computer code instructions stored thereon for carrying out the method according to  claim 1  when executed by a device having processing capability. 
     
     
       12. A device comprising:
 a receiver configured to receive, over a network, first encoded image data representing a scene, the first encoded image data being collected by a camera under a first light condition using first camera parameters, and second encoded image data representing the same scene, the second encoded image data being collected by the camera under the first light condition using second camera parameters which are different from the first camera parameters in that they are modified to increase a level of noise in image data collected by the camera, thereby simulating that the second encoded image data is collected under a second, darker, light condition, and 
 a processing component configured to determine a ratio of received data amount per time unit of the first encoded image data to received data amount per time unit of the second encoded image data, and 
 use the ratio as an indication of a level of noise in the first encoded image data. 
 
     
     
       13. The device of  claim 12 , wherein the processing component is further configured to:
 check if the ratio is larger than a predefined threshold, and if so 
 determine that an action needs to be taken in order to reduce the level of noise in future image data representing the scene collected by the camera under the first light condition using the first camera parameters. 
 
     
     
       14. The device of  claim 13 , wherein the processing component is configured to:
 determine that additional lighting is needed in the scene when the camera uses the first camera parameters to collect image data of the scene under the first light condition. 
 
     
     
       15. A network camera system comprising
 a device according to  claim 12 , and 
 a camera connected to the device via a network, the camera being configured to:
 collect first encoded image data representing a scene, the first encoded image data being collected under a first light condition using first camera parameters, and 
 collect second encoded image data representing the scene, the second encoded image data being collected under the first light condition using second camera parameters which are different from the first camera parameters in that they are modified to increase a level of noise in image data collected by the camera, thereby simulating that the second encoded image data is collected under a second, darker, light condition, and 
 transmit the first and the second encoded image data to the device over the network.